Abstract 20265: Myocardial Blood Flow Quantification with Rubidium-82 Cardiac PET has Incremental Prognostic Value in Patients with Known or Suspected Coronary Artery Disease
Aim: Cardiac PET allows non-invasively assessment of myocardial blood flow (MBF) and myocardial flow reserve (MFR). The impact of MBF and MFR in predicting major adverse cardiovascular events (MACE) has not been investigated in a prospective study, which was our aim.
Material And Methods: In total, 313 patients (65±11y, 36% women) with known or suspected CAD underwent both a rest and adenosine stress cardiac PET/CT with Rubidium-82. Dynamic acquisitions were analyzed semi-quantitatively computing the summed difference score (SDS) and quantitatively using the FlowQuant 2.1.3 software (MBF, MFR). Patients were stratified according to SDS, and allocated into groups of tertiles of stress MBF and MFR. For each group, annualized event rates were computed by dividing the number of annualized MACE (cardiac death, myocardial infarction, revascularisation or hospitalisation for cardiac-related event) by the sum of individual follow-up periods in years. Outcome were analyzed for each group using Kaplan-Meier event-free survival curves and compared using the log-rank test. Multivariate analysis was performed in a stepwise fashion using Cox proportional hazards regression models.
Results: The median follow-up was 256 days (range 168–494d) during which 42 MACE were observed. Ischemia (SDS≥2) was observed in 85 patients for whom annualized MACE rate was higher as compared to those without (60% vs. 8%, p<0.0001). The group with the lowest MFR tertile (MFR<1.7) had higher MACE rate than the two highest tertiles (44% vs.9% and 12%, p<0.0001). Besides, the group with the lowest stress MBF tertile (MBF<1.8mL/min/g) had the highest annualized MACE rate as compared to the two others (37% vs. 21% and 3%, p=0.0001). On multivariate analysis, the addition of MFR or stress MBF to SDS significantly increased the global χ2 (from 60 to 65, p=0.02; and from 60 to 66, p=0.01). The best prognostic power was obtained by combining SDS (p<0.0001) and stress MBF (p=0.006). Interestingly, integrating stress MBF enhanced risk stratification even in absence of ischemia.
Conclusions: Quantification of MBF or MFR in Rb–82 cardiac PET/CT, over semi-quantitative assessment, provides independent and incremental prognostic information and is of significant value for risk stratification.
- © 2010 by American Heart Association, Inc.